Effect of operational factors on bioregeneration of binary phenol and 4-chlorophenol-loaded granular activated carbon...

The effects of dry biomass density in cryogel beads, shaking speed and initial concentration ratio of phenol to 4-chlorophenol (4-CP) on the bioregeneration efficiencies of binary phenol and 4-CP-loaded granular activated carbon (GAC) for phenol and 4-CP, respectively, were investigated under the simultaneous adsorption and biodegradation approach. The results revealed higher bioregeneration efficiencies of binary-loaded GAC for phenol and 4-CP at higher dry biomass density but moderate shaking speed. The optimum dry biomass density in cryogel beads and shaking speed for use in bioregeneration were found to be 0.01 g/mL and 250 rpm, respectively. With respect to the initial phenol to 4-CP concentration ratio, the bioregeneration efficiencies were lower under increasing phenol and 4-CP initial concentrations, respectively, with the effect being more conspicuous under increasing 4-CP concentration. Higher bioregeneration efficiencies were achieved with the use of immobilized rather than suspended biomasses.